ThecricetinerodentPeromyscusleucopusisamajorreservoirforseveralemerginginfectious diseases,includingLymedisease,themostcommonarthropod-?borneinfectioninNorthAmerica.While collectiveworktodatehasidentifiedseveralquantitativetraitsrelevanttounderstandinginter-? individualvariationinananimal?sabilitytoserveasapathogenhost,otherunidentifiedgenesaccount forthebulkofstandinggeneticvariationinthefullrangeofhostresponsesinhumansandotheranimals. Theuseofheterogeneousstocks(HS;apopulationderivedseveraldozengenerationsagofromasmall numberoffounders)isapromisingapproachfordissectingcomplextraitsinthissystem.InthecaseofP. leucopus,aclosedpopulationexists:theLLcolony,whichwasfounded~30yearsagofrom38individuals andhasbeensubsequentlymaintainedatalargepopulationsize.OurpreliminarydatashowthattheLL colonyhasextensivegeneticvariationatSNPs.Furthermore,LDextendsovermuchlongerdistancesthan inwildpopulations,butmuchlessthanamappingpanelofMusmusculus.Assemblyofadraftgenomeof anindividualfromtheLLcolonyisunderway. WewillcarryoutexperimentsexploitingtheLLcolonytoidentifyandlocalizegenesthatcontribute toacomplextraitofrelevancetoparasitismbyahematophagousarthropodvector?bleedingtime,a measureofhemostasis.Bleedingtimeishighlyheritableandcanbeeasilyandreplicablymeasured.In ordertogeneticallydissectbleedingtime,wewillcarryoutaP.leucopusgenomeannotationandSNP identificationproject.WeexpecttoannotateroughlyhalfofallcodingexonsinP.leucopusandidentify over>1MSNPssegregatingintheLLcolony.Wewillthendevelopacost-?effectivescalablemethodfor genotypingP.leucopusindividualsforalargebut?fixed?setofSNPs,andusethismethodtogenotype ~500LLcolonyindividualsonwhichbleedingtimewillalsobemeasured.ThesedataandaHSstrategy willbeemployedtoidentifythegeneticregionsthatcontributetovariationinbleedingtime.The ultimategoalofthistwoyearprojectistodemonstratethattheuniqueLDstructureofLLcolonyP. leucopusmiceallowshigh-?poweredgenome-?wideassociationstudiestobecarriedoutwith~50KSNPs, andtoshowthatidentifiedQTLcanbelocalizedto0.5-?2.0Mbwindows.